Automatic drilling machine



Feb. "I, 19? P. A. TAYSOM ETAL 3,392,494

AUTOMATIC DRILLING MACHINE Filed May 27, 196-4, 5 Sheets-Sheet 1 lnuenlor PATRICK A. TAYSOM ROBEIQT k/RA Feb. 7, 1967 Filed May 27, 1964 P. A. TAYSOM ETAL AUTOMATIC DRILLING MACHINE 5 Sheets-Sheet 2 lnve'nlors PATRICK A. TAYSOM ROGER 7 E. l'f/AK A torney P. A. TAYSOM ETAL 3,302,494

AUTOMATIC DRILLING MACHINE Feb. 7, 1967 5 Sheets-Sheet 5 Filed May 27, 1964 F/GS WM m m MYJW m T a n E [47/ RR ,7 5i ROB T A R P 7, 7 P. A. TAYSOM ETAL 3,

AUTOMA'II C DRILLING MACHINE Filed May 27, 1964 5 Sheets-Sheet 4 Inventors PATR/CK A. TAYSC/Y QOBERT E. k/ Qk Feb. 7, 1967 P. A. TAYSOM ETAL 3,302,494

AUTOMATIC DRILLING MACHINE Filed May 27, 1964 5 Sheets-Sh1eet 5 Inventors PATRICK A 7'14 YSOM R 086'? 7' E. k/A'K A. tlorney United States Patent 3,302,494 AUTOMATIC DRILLING MACHINE Patrick Arnold Taysom, Cardiff, Wales, and Robert Edwin Kirk, Brookmans Park, England, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed May 27, 1964, Ser. No. 370,520 Claims priority, application Great Britain, July 8, 1963, 26,972/ 63 1 Claim. (CI. 77-63) The present invention relates to machine tools, and, more particularly, to a machine for processing materials in sheet or strip form, the processing operations each being performed at a relatively localized part of a workpiece.

The term processing as used herein refers to drilling, punching, forming, slotting, assembling, and other such operations, and the present invention provides a processing machine which has for its work talble an open framework with a rectangular hole the size of which defines the working area. The workpiece is supported by clamps on one side of the framework, and in addition there is a spindle below the work position. The framework and hence the workpiece can be moved with respect to the working position and hence with respect to the spindle.

Although the invention is not so limited, the invention Will be described in its application to a drilling machine; and a drilling machine which embodies the present invention will now be described with reference to the accompanying drawings, in which:

FIGURE 1 is a pictorial view of the drilling machine and of a control unit whereby the operations of the machine can be controlled either by manually operated switches or automatically from a programed tape;

FIGURE 2 is a pictorial view illustrating in more detail than FIGURE 1 the work table, drilling head and immediately adjacent parts;

FIGURE 3 is a simplified sketch illustrating the threepoint suspension of a workpiece;

FIGURE 4 is a perspective view showing (with many parts omitted) the arrangements for positioning the work table in two coordinates;

FIGURE 5 is a side view showing the arrangement of the drill head; and

FIGURE 6 is a schematic diagram of the drivingpulley arrangement.

As can be seen from the general view, FIGURE 1, the machine has a drill head 1, with a six-spindle (i.e. six different drilling positions) turret which can be indexed automatically to allow selection of any one of six drills. These drills are fitted in chucks (see FIGURE 2) and are guided by drill bushings in a turret plate 2, which rotates with the drill turret. The driving arrangements for the turret are such that they allow a range of nine spindle speeds and nine spindle feeds, any of which can be selected automatically under control of the control unit 3. The spindles are driven by a half-horsepower electric motor, and the spindle feed is hydraulically controlled, the drill feed unit being indicated at 4.

The drilling table, whose movements are hydraulically controlled, has (in the example being described) a working area which can take plates of up to 12 inches square. This table (see FIGURE 2) is in the form of a frame, with the workpiece 5 held in position by two clamps 6 mounted on one side of the frame. 'Ilhese clamps are actually mounted on a slide bar 8 extending along the side 7 of the frame. The positions of these clamps are adjusted manually; a scale 9 is provided to facilitate the positioning.

The nature of the table is seen in the simplified sketch, FIGURE 3; here the clamps 6 are shown for simplicity as if they were mounted directly on the frame side 7,

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instead of being mounted on a slide bar, as mentioned above. A workpiece is indicated at 5 in dashed lines. When drilling is in progress, the workpiece is supported at the actual point of drilling by a spindle whose uppermost end is indicated at 10. This spindle has a hollow portion which receives the end of a drill during operation, and being retractable, is retracted between drillings to clear drill chips.

The arrangements for coordinate positioning of the worktable are shown in FIGURE 4. Here the frame 12 is shown slidably mounted on two rods 13, 14 which are journaled within the frame in ball bearings to minimize friction. Movement in the Y direction is effected 'by a drive shaft 15 which works on a sleeve 16, the latter being on a shaft 17 so that movement in the X direction does not affect the drive shaft. The shaft 17 is mounted on a pair of brackets at the back of the table 12, and is journaled within the sleeve 16 in ball bearings to minimize friction.

The two support and guide rods 13, 14 have their ends supported on V-shaped notches in the two sides of a further frame 18. Caps may be placed over the notches when the rods are in place. The frame 18 is movable in the X direction along a further pair of guide rods 19, 20 journaled in ball hearings in the frame 18 and also journaled in capped V notches as can be seen from the drawing. The X di-rection movement is imparted to the frame 18, and hence to the worktable, by a drive shaft 21 acting on the frame.

The two drive shafts are each movable in the positive and negative directions as indicated by the arrows placed alongside them in FIGURE 4, the extent of movement being limited by position control arrangements such as those of British Patent No. 870,186 (P. A. Taysom). However, the position control arrangments are not shown in the drawings.

Referring to FIGURE 2 again, the frame which forms the worktable has a retractable stop 22, which serves to locate the workpiece accurately. This retractable stop is shown in FIGURE 2 in its non-retracted position although it is retracted when in use so as to preclude interference with the turret plate 2.

One point about the worktable which has not been mentioned as yet is that is has two wings 23, 24, 25, 26, at each side as shown in FIGURE 2 (these being omitted from FIGS. 3 and 4 in the interests of simplicity). These wings serve to support the ends of long strip-like workpieces being dealt with. Hence, although the drilling area is restricted to 12" square (in the case of the machine described herein) for any one setting of a workpiece, the manual control system is so arranged that the workpiece can be repositioned along the X axis, using a previously drilled hole as a new datum position. Hence, workpieces longer than 12", with drillings along the .whole length can be dealt with.

The arrangement of the drill proper is shown in FIG- URE 5, which shows the turret 1, the drill-feed unit 4 and the turret plate 2 already mentioned. The turret and turret plate are coupled by two shafts 30 (see also FIGURE 2) on which the turret unit is slidably mounted. The turret plate 2 has a control device 31 controlled so that when the turret is indexed, the turret plate is correspondingly indexed. The indexing is effected hydraulically under control of the control unit 3, as will be mentioned later. The lower ends of the shafts 30 are journaled in a casing 32, above the turret plate 2.

The whole drill unit including the turret 1 is movable up and down, so that the drive shaft 33, via which drive reaches the drill to be used, has a flexible coupling (not shown). Also shown in FIGURE 5 is the position of the clamps, dotted at 34, and the spindle 10 in its retracted and non-retracted positions.

Coolant for the drill (shown in FIGURE 2) and also for the workpiece is supplied to the working point v1a a pipe 36 whose lower end is near the bushing plate. The machine itself has a coolant tray 37 (see FIGURE 1) for catching the coolant.

Now it is necessary to describe briefly the control unit 3, shown in FIGURE 1, which allows the machine to work unattended (except for loading and unloading) under control of a programed tape. In the arrangement shown, punched tape is used, being read by an electromechanical tape reader of known type. However, a photoelectric tape reader could be used for this purpose; and in fact, such a device may be preferable as it has fewer moving parts than does an electromechanical reader.

The control unit has a number of multi-position switches 38, and also an indicator panel 39 with lamp indicators for representing the settings of the various controlled entities of the machine. There are also faultindicator lamps on the control circuit. Finally, there is an on-olf switch unit 40.

The drive shaft 33 for the drill receives its power from an electric motor whose drive is applied via two stages of belt drive, as schematically indicated in FIG. 6, in which a first pulley 60 is shown, this being the driver pulley, rotated by the electric motor. Pulley 60 drives an idler pulley 61 by a multi-V belt 62, this pulley 61 being mounted on a slidable block so that it can move along a slot at right angles to a radius struck from the center of the pulley 60.

Pulley 61, or a second pulley rotatable therewith, drives the first or driving pulley 63 via a further multi-V belt 64. The pulley 63 is mounted on the vertically-adjustable drill head carriage, and is movable up and down by 6", its other extreme position being shown in broken lines at 63. The centers of the pulleys 63 and 61 are maintained a constant distance apart by a connecting link (not shown).

Thus, if the driving pulley 63 moves vertically, as it does when the drill head moves vertically, it moves the pulley 61 along a path at right angles to the radius struck from the center of the pulley 60, so that a constant belt length is maintained between pulleys 61 and 63 and very nearly a constant length between pulleys 60 and 61. There is, in fact, a variation of about of the length of the belt between pulleys 6t) and 61 over the full adjustment of 6" of pulley 63 because the pulley 61 follows a straight path, but this is taken up by the flexibility of the rubberized belt.

These pulleys and the motor are in the casing behind the drill turret 1 (FIGURE 1).

The variable-speed device for varying the speed of the drive to the spindle on the drilling machine has a rotatable control shaft which can be angularly adjusted either clockwise or counterclockwise, to select the required speed. This is achieved by driving the shaft through an electro-magnetic clutch by a reversible electric motor, which also drives, through a gear change, a multiposition rotary switch. Selection of a required speed on the operators console or by punched tape energizes one of the contacts on the rotary switch, energizes the electromagnetic clutch, and starts the electric motor. When the wiper arm of the rotary switch reaches the energized contact, the electromagnetic clutch is tie-energized, thus de-coupling the speed control shaft which then stops. It is now in the position appropriate to the speed required.

The electrical supply to the motor is cut at the same instant as the electromagnetic clutch is de-energized, and the motor stops after a short over-run period. The function of the electromagnetic clutch is two-fold:

(a) To provide immediate de-clutching of the speedcontrol shaft independent of the over-run to the motor and (b) To act as a safety clutch which will slip and prevent damage to the speed-control device for the motor, should the motor fail to stop when required.

When a new speed is selected, the control circuit automatically senses whether the new speed is faster or slower than the previous speed and instructs the motor to rotate clockwise or counterclockwise, accordingly.

The above-mentioned shaft control governs in a well known manner the speed at which the motor which drives the drill runs. These elements are also in the casing of FIGURE 1.

The feed of the drill head is effected by hydraulic cylinder 4; to vary the feed speed, a variable hydraulic flow is used to vary the flow of oil from the hydraulic cylinder. By varying the flow of oil, the speed of movement of the cylinder, and thus the feed rate of drilling, is varied.

The requirement is to select any one of nine feeds, and this is achieved by actuating the flow valve by a hydraulic cylinder via a rack-and-pinion drive. Also driven by the rack, through a further pinion, is a multi-contact rotary switch.

Selection of the required feed, on the operators console or by punched tape, energizes one of the contacts of the rotary switch, and operates a solenoid valve to start the hydraulic cylinder movement. This, in turn, rotates both the flow-control valve and the wiper arm on the rotary switch. When the wiper arm reaches the energized contact, the hydraulic cylinder is stopped, thus leaving the flow valve set at the required position. The hydraulic cylinder which positions the flow valve is additional to that used for the drill feed.

When a new feed is selected, the control circuit automatically senses whether the new feed is greater or lesser than the previous feed and instructs the hydraulic cylinder to move forward or backward accordingly.

Having described the general characteristics of the machine, a sequence of operations will now be described. The operator loads the workpiece with the clamps 6 correctly located and then operates a switch to close the clamps and retract the location stop. The start button (on the unit 40) is then pressed, initiating the following automatic cycle (assuming that a tape is in position):

(a) Part of the first block of information on the punched tape is read by the reader, and enters the control circuitry. This, and all subsequent information on the tape, is in a binary-coded decimal notation.

(b) The table is moved by the hydraulic rams controlled by the position-control units, so that it is correctly positioned. Movement can occur during this positioning in both axes simultaneously, and when the movement is completed the table is clamped.

(0) During the table positioning, the remainder of the same block of information is read, this remainder relating to the spindle feed and speed selections (these will in general depend on the nature and on the thickness of the workpiece) and also the turret index instructions. This information is also fed into the control circuitry.

(d) The required spindle feed and speed are selected, the turret (and with it the turret plate) indexed, if not already in the correct positions, and the drill head advanced so that the chosen drill drills, whereafter the drill retracts.

(e) During the action given at (d) above, the table movement instructions of the next cycle, i.e. for the next hole to be drilled, are read and fed to the control circuitry. Hence immediately the head has been retracted the table is unclamped, repositioned and clamped again.

The above cycle of operations is repeated automatically until all the holes are drilled, when the machine stops to allow the operator to reload. For convenience, the tape is joined at its ends so that a closed loop is formed, whereby the tape is ready to start the next cycle.

If coolant is needed during the operation, it is applied automatically (under control of the data from the tape) during the drilling cycle only, so that the coolant only flows while the drillhead is in motion.

In the early part of this specification it was mentioned that material processings other than drilling are possible in a machine such as described above. In such case it will be realized that the guide bushings in the turret plate would need to be suitably chosen as would the upper end configuration of the spindle 10.

While We have described the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention, as set forth in the accompanying claim.

We claim:

In an automatic drilling machine, a drilling table and means for positioning said drilling table and a workpiece carried thereby with respect to the drill bit of said drilling machine, said drilling table comprising a four-sided frame open in the center for accommodating said workpiece and a plurality of clamps positioned on one side of said four-sided frame for holding an edge of said workpiece, said drilling table having in cooperative arrangement therewith a centrally located spindle for supporting said workpiece at a point directly opposite the drilling position of said drill bit, said means for positioning said drilling table comprising a pair of parallel rods and a frame in which said parallel rods are journaled, said drilling table being slidable upon said parallel rods, a shaft mounted on two brackets respectively positioned on either side of said drilling table and passing through a sleeve, a drive shaft coupled to said sleeve for moving said drilling table in a direction parallel to said pair of rods, said pair of rods being in turn supported by a foursided frame, said frame being movable in a direction orthogonal to the direction in which said drilling table slides upon said pair of rods, said frame having means for moving it in said orthogonal direction to impart a second dimension to the positioning of said drilling table and said workpiece with respect to said drill bit.

References Cited by the Examiner UNITED STATES PATENTS 277,817 5/1883 Wilder et al 77-64 444,810 1/1891 Bonner 77-63 514,762 2/1894 Maier 144-93 1,724,250 8/1929 Berven 77-25 2,269,946 1/1958 Lange 144-93 2,819,743 1/1958 Birkel et al. 143-48 2,975,661 3/1961 Coleman 77-5 3,064,505 11/1962 Pierce 77-63 3,116,652 1/1964 Bregnard 77-5 3,124,018 3/1964 Gough 77-63 3,138,974 6/1964 Burg 77-25 3,183,780 5/1965 Little 77-63 3,192,801 7/1965 Gingras 77-5 FRANCIS S. HUSAR, Primary Examiner. 

